Polynucleotides encoding anti-CD40 antibodies

ABSTRACT

The present invention relates to antibodies specific for a particular epitope on CD40 and antibodies that bind CD40 and have particular functional characteristics. The present invention also relates to fragments of these antibodies, uses of the antibodies for reduction or treatment of transplant rejection and graft-versus-host disease, and methods for making the antibodies.

STATEMENT AS TO FEDERALLY FUNDED RESEARCH

This invention was made with government support under GrantHHSN272200900037C awarded by NIH. The Government has certain rights inthe invention.

BACKGROUND OF THE INVENTION

The invention relates to anti-CD40 antibodies and uses of suchantibodies, for example, to reduce the likelihood of, or increase theduration prior to, transplant rejection, to induce immunosuppression, orto treat an autoimmune disorder.

Suppression of the immune system, particularly the humoral immunesystem, is beneficial in organ transplantation and treatment ofautoimmune disorders. Organ transplantation, for example, has emerged asa preferred method of treatment for many forms of life-threateningdiseases that involve organ damage. Transplantation rejection occurswhen an organism receiving transplanted cells or tissue mounts anundesired immune response to that tissue. Transplant rejection can beminimized by tissue-type matching, but even matched tissue is generallyrejected by the donor. Thus, immunosuppressive therapies are requiredfor virtually all cases of tissue transplantation.

Improved results in clinical transplantation have been achievedprimarily through the development of increasingly potent non-specificimmunosuppressive drugs to inhibit rejection responses. While short-termresults have improved, long-term outcomes remain inadequate. Life-longimmunosuppressive agents may be required to combat chronic rejection ofthe transplanted organ, and the use of these agents dramaticallyincreases the risks of cardiovascular disease, infections, andmalignancies.

One potential target for reducing transplantation rejection is theCD40/CD154 interaction. CD40 is expressed on the surface B lymphocytesand CD154 is expressed on surface of T cells. The interaction betweenthese two proteins is associated with B cell activation, which triggerscytokine expression as well as expression of cell surface markersincluding CD23, CD80, and CD86. Blockade of this interaction usinganti-CD154 antibodies has been shown to reduce or eliminate rejection oftransplanted tissues in non-human primates.

For any type of immunosuppression (e.g., in a transplantationprocedure), a balance between efficacy and toxicity is a key factor forits clinical acceptance. Thus, there is a need for therapies thatspecifically target the immunological pathways involved in, for example,transplant rejection and autoimmune disorders.

SUMMARY OF THE INVENTION

In a first aspect, the invention features an isolated antibody, orantigen-binding fragment thereof (e.g., an antibody that lacks an Feportion or is a F(ab′)₂, a Fab, an Fv, or an scFv structure), thatspecifically binds to an epitope present on CD40 (e.g., rhesus, murine,or human CD40), where the epitope is recognized by the 2C10 antibody(e.g., where said epitope is not recognized by the 3A8 or the Chi220antibody, or both). The antibody may be capable of blocking B lymphocyte(e.g., rhesus or human B lymphocyte) activation by CD154-expressingJurkat cells in vitro or may be capable of inhibiting rhesus B cells invitro, e.g., reducing CD23, CD80, or CD86 expression. The antibody maybe the 2C10 antibody. The antibody may have human constant regions. Incertain embodiments, the antibody is a humanized antibody or a humanantibody. In certain embodiments, the antibody may be monoclonalantibody or a polyclonal antibody.

In particular embodiments, the antibody includes the heavy chainvariable region defined by amino acids 20-132 of SEQ ID NO:2, anantibody-binding portion or fragment thereof, or a humanized formthereof. In other embodiments, the antibody light chain variable regionof the antibody includes the sequence of 23-128 of SEQ ID NO:4, anantibody binding portion or fragment thereof, or a humanized formthereof. In other embodiments, the heavy chain variable region of theantibody includes amino acids 20-132 of SEQ ID NO:2 and the light chainvariable sequence of the antibody includes amino acids 23-128 of SEQ IDNO:4.

The invention also features a polynucleotide encoding the antibody orantibody fragment of the first aspect, a vector including thepolynucleotide, and a cell including the vector. The cell may beeukaryotic (e.g., mammalian such a human, mouse, monkey or rabbit cell)or may be prokaryotic (e.g., a bacterial cell such as an E. coli cell).

In another aspect, the invention features a method of suppressing theimmune system in a subject (e.g., a mammal such as human). The methodincludes administering to the subject an effective amount of anantibody, or antigen-binding fragment thereof, of the first aspect tothe subject.

In yet another aspect, the invention features a method of treating ortreating prophylactically transplant rejection or increasing theduration of time before transplant rejection occurs in a subject (e.g.,a mammal such as a human) in need thereof. The method includesadministering an effective amount of an antibody, or antigen-bindingfragment thereof, of the first aspect to the subject.

In either of the previous two aspects, the subject may have received, ormay be in need of, an organ transplant (e.g., a heart, kidney, lung,liver, pancreas, intestine, and thymus, or a portion thereof) or atissue transplant (e.g., bone, tendon, cornea, skin, heart valve, vein,or bone marrow).

In any of the previous two aspects, administration may be commencedprior to the transplantation or the graft. Administration may continuefor at least 1, 2, 3, 4, 5, 7 or 10 days; 2, 3, 4, 6, 8, 10, or 12weeks; 3, 4, 5, 6, 8, 10, 12, 24, or 36 months following thetransplantation or the graft.

In yet another aspect, the invention features a method of treating ortreating prophylactically graft-versus-host disease in a subject (e.g.,a mammal such as a human) in need thereof. The method includesadministering an effective amount of an antibody, or an antigen-bindingfragment thereof, of the first aspect to the subject.

In another aspect, the invention features a method of treating ortreating prophylactically an autoimmune disorder in a subject (e.g., amammal such as a human) in need thereof. The method includesadministering an effective amount of an antibody, or an antigen-bindingfragment thereof, of the first aspect to the subject. In certainembodiments, the autoimmune disorder is associated with or caused by thepresence of an autoantibody (e.g., systemic lupus erythematosus (SLE),CREST syndrome (calcinosis, Raynaud's syndrome, esophageal dysmotility,sclerodactyl, and telangiectasia), opsoclonus, inflammatory myopathy(e.g., polymyositis, dermatomyositis, and inclusion-body myositis),systemic scleroderma, primary biliary cirrhosis, celiac disease (e.g.,gluten sensitive enteropathy), dermatitis herpetiformis, Miller-FisherSyndrome, acute motor axonal neuropathy (AMAN), multifocal motorneuropathy with conduction block, autoimmune hepatitis, antiphospholipidsyndrome, Wegener's granulomatosis, microscopic polyangiitis,Churg-Strauss syndrome, rheumatoid arthritis, chronic autoimmunehepatitis, scleromyositis, myasthenia gravis, Lambert-Eaton myasthenicsyndrome, Hashimoto's thyroiditis, Graves' disease, Paraneoplasticcerebellar degeneration, Stiff person syndrome, limbic encephalitis,Isaacs Syndrome, Sydenham's chorea, pediatric autoimmuneneuropsychiatric disease associated with Streptococcus (PANDAS),encephalitis, diabetes mellitus type 1, and Neuromyelitis optica). Inother embodiments, the disorder is selected from the group consisting ofpernicious anemia, Addison's disease, psoriasis, inflammatory boweldisease, psoriatic arthritis, Sjögren's syndrome, lupus erythematosus(e.g., discoid lupus erythematosus, drug-induced lupus erythematosus,and neonatal lupus erythematosus), multiple sclerosis, and reactivearthritis. In still other embodiments, the disorder is selected from thegroup consisting of polymyositis, dermatomyositis, multiple endocrinefailure, Schmidt's syndrome, autoimmune uveitis, adrenalitis,thyroiditis, autoimmune thyroid disease, gastric atrophy, chronichepatitis, lupoid hepatitis, atherosclerosis, prescnile dementia,demyelinating diseases, subacute cutaneous lupus erythematosus,hypoparathyroidism, Dressler's syndrome, autoimmune thrombocytopenia,idiopathic thrombocytopenic purpura, hemolytic anemia, pemphigusvulgaris, pemphigus, alopecia arcata, pemphigoid, scleroderma,progressive systemic sclerosis, adult onset diabetes mellitus (e.g.,type II diabetes), male and female autoimmune infertility, ankylosingspondolytis, ulcerative colitis, Crohn's disease, mixed connectivetissue disease, polyarteritis nedosa, systemic necrotizing vasculitis,juvenile onset rheumatoid arthritis, glomerulonephritis, atopicdermatitis, atopic rhinitis, Goodpasture's syndrome, Chagas' disease,sarcoidosis, rheumatic fever, asthma, recurrent abortion,anti-phospholipid syndrome, farmer's lung, erythema multiforme, postcardiotomy syndrome, Cushing's syndrome, autoimmune chronic activehepatitis, bird-fancier's lung, allergic disease, allergiccncephalomyelitis, toxic epidermal necrolysis, alopecia, Alport'ssyndrome, alveolitis, allergic alveolitis, fibrosing alveolitis,interstitial lung disease, erythema nodosum, pyoderma gangrenosum,transfusion reaction, leprosy, malaria, leishmaniasis, trypanosomiasis,Takayasu's arteritis, polymyalgia rheumatica, temporal arteritis,schistosomiasis, giant cell arteritis, ascariasis, aspergillosis,Sampter's syndrome, eczema, lymphomatoid granulomatosis, Behcet'sdisease, Caplan's syndrome, Kawasaki's disease, dengue, endocarditis,endomyocardial fibrosis, endophthalmitis, erythema elevatum et diutinum,erythroblastosis fetalis, eosinophilic faciitis, Shulman's syndrome,Felty's syndrome, filariasis, cyclitis, chronic cyclitis, heterochroniccyclitis, Fuch's cyclitis, IgA nephropathy, Henoch-Schonlein purpura,graft versus host disease, transplantation rejection, humanimmunodeficiency virus infection, echovirus infection, cardiomyopathy,Alzheimer's disease, parvovirus infection, rubella virus infection, postvaccination syndromes, congenital rubella infection, Hodgkin's andnon-Hodgkin's lymphoma, renal cell carcinoma, multiple myeloma,Eaton-Lambert syndrome, relapsing polychondritis, malignant melanoma,cryoglobulinemia, Waldenstrom's macroglobulemia, Epstein-Barr virusinfection, mumps, Evan's syndrome, and autoimmune gonadal failure.

In any of the previous three aspects, administration may be parenteral,intravenous, subcutaneous, oral, topical, intrathecal, local, or by anyroute described herein.

In any of the previous four aspects, the method may further includeadministration of second agent within six months (e.g., within 3, 2, or1 months; within 4, 3, 2, or 1 weeks; within 6, 5, 4, 3, 2, or 1 days;or within 18, 12, 6, 3, 2, or 1 hours of antibody administration), wherethe second agent is an immunosuppressant. The second agent may beselected from the group consisting of a calcineurin inhibitor (e.g.,cyclosporin A or cyclosporine G), tacrolimus, an mTor inhibitor (e.g.,sirolimus, temsirolimus, zotarolimus, or everolimus), fingolimod,myriocin, alemtuzumab, rituximab, an anti-CD4 monoclonal antibody, ananti-LFA1 monoclonal antibody, an anti-LFA3 monoclonal antibody, ananti-CD45 antibody (e.g., an anti-CD45RB antibody), an anti-CD19antibody, monabatacept, belatacept, indolyl-ASC; azathioprine,lymphocyte immune globulin and anti-thymocyte globulin [equine],mycophenolate mofetil, mycophenolate sodium, daclizumab, basiliximab,cyclophosphamide, prednisone, prednisolone, leflunomide, FK778, FK779,15-deoxyspergualin, busulfan, fludarabine, methotrexate,6-mercaptopurine, 15-deoxyspergualin, LF15-0195, bredinin, brequinar,and muromonab-CD3. In certain embodiments, the second agent isbelatacept.

In still another aspect, the invention features a method of making anantibody. The method includes: (a) administering to a mammal (e.g., amouse or a rabbit) a polypeptide that comprises a fragment (e.g., lessthan 50, 40, 30, 20, 10 amino acids in length, but more than 6, 8, or 10amino acids in length) of the CD40 polypeptide that includes the epitoperecognized by the 2C10 antibody, but not the full length CD40 moleculein a manner sufficient to generate an immune response to said fragment;(b) isolating spleen cells from the mammal; (c) forming a hybridomabetween the spleen cells and myeloma cells; and (d) purifying theantibody produced by the hybridoma. The polypeptide may be a fusionprotein (e.g., between the CD40 fragment and keyhole limpet hemocyaninor glutathione S-transferase). The invention also features an antibodyproduced by such a method.

In another aspect, the invention features a fragment of CD40 fewer than150 (e.g., fewer than 120, 100, 80, 70, 60, 50, 40, 30, 20, 15, 12, 11,10, 9, 8, or 7) amino acids in length that is specifically bound by the2C11 antibody. In certain embodiments, the fragment is 8-10, 8-12, 8-15,8-20, 8-30, 8-40, 8-50, 8-60, 8-70, 8-80, or 8-100 amino acids inlength. In other embodiments, the fragment is 7-10, 7-12, 7-15, 7-20,7-30, 7-40, 7-50, 7-60, 7-70, 7-80, or 7-100 in length. The CD40fragment may be from the extracellular domain of CD40 (e.g., SEQ IDNOS:5 and 6). The invention also features a fusion protein including afragment described herein and a heterologous sequence.

By “specifically binds” is meant a compound or antibody that recognizesand binds a particular epitope but does not substantially recognize andbind other molecules present in a sample (e.g., a biological samplewhich naturally includes other polypeptides, nucleic acids, and/or otherbiological molecules). In one example, an antibody that specificallybinds the CD40 epitope recognized by the 2C10 antibody does not bindother epitopes present on CD40.

By “antigen-binding fragment” of an antibody is meant any fragment orportion of an antibody that has the ability to specifically bind thetarget antigen of the full length antibody.

“Humanized” forms of non-human (e.g., murine) antibodies are chimericantibodies that contain minimal sequence derived from non-humanimmunoglobulin. In one embodiment, a humanized antibody is a humanimmunoglobulin (recipient antibody) in which residues from ahypervariable region (HVR) of the recipient are replaced by residuesfrom a HVR of a non-human species (donor antibody) such as mouse, rat,rabbit, or nonhuman primate having the desired specificity, affinity,and/or capacity. In some instances, framework (FR) residues (i.e.,residues in the variable regions other than the hypervariable regions)of the human immunoglobulin are replaced by corresponding non-humanresidues. Furthermore, humanized antibodies may comprise residues thatare not found in the recipient antibody or in the donor antibody. Thesemodifications may be made to further refine antibody performance. Ingeneral, a humanized antibody can comprise substantially all of at leastone, and typically two, variable domains, in which all or substantiallyall of the hypervariable loops correspond to those of a non-humanimmunoglobulin, and all or substantially all of the FRs are those of ahuman immunoglobulin sequence. The humanized antibody optionally willalso comprise at least a portion of an immunoglobulin constant region(Fc), typically that of a human immunoglobulin. For further details,see, e.g., Jones et al., Nature 321:522-25, 1986; Riechmann et al.,Nature 332:323-29, 1988; and Presta, Curr. Op. Struct. Biol. 2:593-6,1992. See also, e.g., Vaswani et al., Ann. Allergy Asthma & Immunol.1:105-15, 1998; Harris, Biochem. Soc. Transactions 23:1035-8, 1995;Hurle et al., Curr. Op. Biotech. 5:428-33, 1994; and U.S. Pat. Nos.6,982,321 and 7,087,409.

A “human antibody” is one that possesses an amino acid sequencecorresponding to that of an antibody produced by a human and/or has beenmade using any of the techniques for making human antibodies asdisclosed herein. This definition of a human antibody specificallyexcludes a humanized antibody comprising non-human antigen-bindingresidues. Human antibodies can be produced using various techniquesknown in the art, including phage-display libraries (Hoogenboom et al.,J. Mol. Biol 227:381-8, 1992; Marks et al., J. Mol. Biol, 222:581-97,1991). Also available for the preparation of human monoclonal antibodiesare methods described in Cole et al., Monoclonal Antibodies and CancerTherapy, Alan R. Liss, p. 77 (1985); Boemer et al., J. Immunol.147:86-95, 1991. See also van Dijk et al., Curr. Opin. Pharmacol.5:368-74, 2001. Human antibodies can be prepared by administering theantigen to a transgenic animal that has been modified to produce suchantibodies in response to antigenic challenge, but whose endogenous locihave been disabled, e.g., immunized xenomice (see, e.g., U.S. Pat. Nos.6,075,181 and 6,150,584 regarding XenoMouse® technology). See also, forexample, Li et al., Proc. Natl. Acad. Sci. USA 103:3557-62, 2006regarding human antibodies generated via a human B-cell hybridomatechnology.

By “treating” a disease, disorder, or condition in a subject is meantreducing at least one symptom of the disease, disorder, or condition byadministrating a therapeutic agent to the subject.

By “treating prophylactically” a disease, disorder, or condition in asubject is meant reducing the frequency of occurrence or severity of(e.g., preventing) a disease, disorder or condition by administering tothe subject a therapeutic agent to the subject prior to the appearanceof a disease symptom or symptoms.

The term “an effective amount” means the dose needed to effectivelytreat the physiological effects of a medical condition (e.g., transplantrejection or graft-versus-host disease).

By “immunosuppressant” is meant a compound or composition that inducesimmunosuppression, i.e., it reduces (e.g., prevents) or interferes withthe development of an immunologic response (e.g., cellular or humoral).

By “subject” is meant a human or non-human animal (e.g., a mammal).

By “fusion protein” is meant a polypeptide that contains (a) a proteinor fragment thereof of interest; and (b) a heterologous fusion partner.

Other features and advantages of the invention will be apparent from thefollowing Detailed Description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the variable regions from the heavy chain and the lightchain of the 2C10 antibody. The nucleotide sequence shown for the heavychain (SEQ ID NO: 1) includes a signal peptide (nucleotides 1-57;underlined) and the heavy chain variable sequence (nucleotides 58-396).The corresponding amino acid sequence is shown below (SEQ ID NO:2),where amino acids 1-19 corresponding to the signal sequence (underlined)and amino acids 20-132 correspond to the heavy chain variable region.

The nucleotide sequence shown for the light chain (SEQ ID NO:3) includesa signal peptide (nucleotides 1-66; underlined) and the light chainvariable sequence (nucleotides 67-384). The corresponding amino acidsequence is shown below (SEQ ID NO:4), where amino acids 1-22 correspondto the signal peptide (underlined) and amino acids 23-128 correspond tothe light chain variable region.

FIG. 2A is a plot showing flow cytometry data confirming the binding of2C10 to human and rhesus CD20+ B cells.

FIG. 2B is a plot showing CD40 adsorption data from ELISA assays withvarying concentrations of 2C10 to confirm the binding of 2C10 to humanand rhesus CD40 as detected using goat anti-mouse IgG-HRP.

FIG. 3 is a graph showing the dose-dependent inhibition of CD154 bindingto B cells by 2C10. B cells were analyzed for CD154 binding byincubating with histidine-tagged soluble CD154 and analyzing forhistidine expression. Results are representative of multiple repetitionsof the experiment.

FIG. 4 is a schematic diagram and graphs showing the principle of theassay involving rhesus or human peripheral blood mononuclear cells(PBMCs) and Jurkat cells.

FIG. 5 is a set of graphs showing CD23 expression in CD20⁺ cells takenfrom co-cultures of rhesus PBMCs and Jurkat cells in the presence ofvariable concentrations of 3A8, 5C8, or 2C10 antibodies.

FIG. 6 is a set of graphs showing CD86 expression in CD20⁺ cells takenfrom co-cultures of human PBMCs and Jurkat cells in the presence ofvariable concentrations of 3A8, 5C8, or 2C10 antibodies.

FIG. 7 is a set of graphs showing CD23 expression CD20⁺ cells fromeither human or rhesus PBMCs cultured without Jurkat cells in thepresence of either the 3A8 or the 2C10 antibody.

FIG. 8 is a graph showing peripheral B cell count of rhesus macaquestreated with mouse-rhesus chimeric forms of 2C10 engineered to containeither rhesus IgG1 (2C10R1) or IgG4 (2C10R4) heavy chain constantregions, and chimeric IgG1 forms of anti-CD40 3A8 (3A8R1) or anti-CD40Chi220 (Chi220). All animals were immunized with4-hydroxy-3-nitrophenylacetyl-conjugated keyhole limpet hemocyanin (KLH)after the first antibody treatment.

FIG. 9 is a graph showing T cell-dependent antibody responses in macaquemonkeys treated with 2C10R1, 2C10R4, or 3A8R1 antibody. All animals wereimmunized with KLH after the first antibody treatment.

FIG. 10 is a diagram showing the standard macaque model of allogeneicislet transplantation. Diabetes was induced in macaque monkeys usingstreptozotocin. Diabetic monkeys were transplanted with allogeneicislets and immunosuppresion initiated with basiliximab and sirolumus.Experimental animals received 2C10R4 treatment on days 0 and 7post-transplantation.

FIG. 11A is a plot showing free blood glucose levels (FBG) in 4 macaquesfollowing islet transplantation, background immunosuppresion, andtreatment with 2C10R4. The solid line on the plot represents the levelof 2C10 in the plasma.

FIG. 11B is a plot showing FBG in macaques that received only backgroundimmunosuppresion.

FIG. 12 is a graph showing results from a competitive blockade assayusing human PBMCs incubated with increasing concentrations of 2C10, 3A8,or Chi220 antibodies and stained with an APC-conjugated 2C10 to assessthe ability of each antibody to cross-block 2C10.

DETAILED DESCRIPTION

The present invention relates to anti-CD40 antibodies and antibodyfragments having the ability to bind a particular epitope on the CD40molecule, as well as methods that involve the use of such antibodies.This epitopic specificity confers a particular activity profile, suchthat the antibodies generally block the ability of CD40 to interact withits binding partners (e.g., CD154) and do so without activating the cellexpressing CD40. This activity profile is understood to make theseantibodies particularly useful for reducing complications associatedwith organ or tissue transplantation.

Production and Identification of CD40 Antibodies

Mice (strain AJ) were immunized with a fusion protein consisting of theextracellular domain of rhesus macaque (M. mulatta) CD40 (amino acidsequence:EPPTACREKQYLINSQCCSLCQPGQKLVSDCTEFTETECLPCSESEFLDTWNRETRCHQHKYCDPNLGLRVQQKGTSETDTICTCEEGLHCMSESCESCV; SEQ ID NO:5) fused to maltosebinding protein (CD40-MBP). The amino acid sequence in this region ofthe rhesus macaque CD40 protein differs from human CD40 protein at fiveamino acid positions (human amino acid sequence:EPPTACREKQYLINSQCCSLCQPGQKLVSDCTEFTETECLPCGESEFLDTWNRETHCHQHKYCDPNLGLRVQQKGTSETD TICTCEEGWHCTSEACESCV; SEQ ID NO:6). CD40-MBP wasadministered to mice multiple times with complete Freund's adjuvant andincomplete Freund's adjuvant. Splenocytes from immunized mice were fusedwith the mouse myeloma cell line SP2/0 and hybrids selected usingstandard hybridoma technology.

Antibodies were selected for reactivity to a second fusion proteinconsisting of the same rhesus CD40 domain fused to glutamine synthetase(CD40-GST). Antibodies reactive to CD40-GST by ELISA were further testedfor reactivity to native CD40 express on rhesus macaque blood B cells,human blood B cells and rhesus macaque B-lymphoblastoid cell lines byflow cytometry. As a final level of selection, antibodies were tested inan in vitro assay for their ability to inhibit human or rhesus macaque Bcell activation after co-culture CD154-expressing Jurkat D1.1 cells. Astable subclone of anti-CD40 antibody 2C10 was obtained by limitingdilution. The antibody is a mouse IgG1-kappa.

Antibody Cloning

Variable regions of monoclonal antibodies can be cloned using any methodknown in the art. PCR-based methods for obtaining antibody variableregion sequences for hybridoma cells are described, for example, inLarrick et al., Nat. Biotechnol. 7:934-8, 1989 and in Orlandi et al.,Proc. Natl. Acad. Sci. USA 86:3833-7, 1989. Using these techniques orsimilar techniques, the variable regions of monoclonal antibodies can becloned and subject to further manipulation.

In the present case, the variable sequences from the heavy and lightchains of the 2C10 antibody were cloned and were sequenced. The DNArepresenting the immunoglobulin heavy and light chain variable regionsfrom the 2C10 hybridoma were cloned using 5′ RACE PCR employing thefollowing DNA primers:

Mouse kappa reverse: (SEQ ID NO: 7)5′-CTA ACA CTC ATT CCT GTT GAA GCT CTTGAC; Mouse kappa forward:(SEQ ID NO: 8) 5′-GCT GAT GCT GCA CCA ACT GTA TCC-3′ Mouse IgG1 reverse:(SEQ ID NO: 9) 5′-GGC AAC GTT GCA GGT CTC GC-3′ Mouse IgG1 forward:(SEQ ID NO: 10) 5′-CTG GAT CTG CTG CCC AAA CTA ACT CC-3′PCR products were cloned into a commercial cloning vector and weresequenced using standard sequencing techniques. The resulting sequencesare provided in FIG. 1.

The immunoglobulin variable region genes were cloned from the hybridomassecreting anti-CD40 antibody clone 2C10 and from anti-human CD40 clone3A8 (Kwekkeboom et al., Immunology 79:439-44, 1993) (obtained from theAmerican Type Culture Collection, ATCC, Vienna, Va.) using 5′ rapidamplification of cDNA ends-polymerase chain reaction. The immunoglobulinheavy and light chain variable regions were subcloned into expressionvectors containing rhesus IgG1 or rhesus IgG4 heavy chain and rhesuskappa light chain constant region sequences.

Recombinant heavy and light chains were subcloned into expressionvectors and packaged in retroviral vectors used to transduce Chinesehamster ovary cells using the GPEx™ expression technology (CatalentPharma Solutions, Middleton, Wis.). A pool of transduced cells was grownin serum-free medium and secreted antibody was purified by protein Aaffinity chromatography. The purified chimeric rhesus IgG1 (2C10R1,3A8R1) and IgG4 (2C10R4) antibodies were diafiltered into phosphatebuffer; endotoxin levels were confirmed to be less than 1 endotoxinunit/mg.

Antibody Characterization

2C10 Binds to CD40 and Prevents Binding of CD154

To assess the ability of 2C10 to bind to both rhesus and human CD40,recombinantly expressed human or rhesus CD40 were adsorbed to ELISAplates and reacted with varying concentrations of 2C10. Binding of 2C10to CD40 was detected using goat anti-mouse IgG-HRP in an ELISA. Theresults in FIG. 2B show that 2C10 have similar binding affinities torhesus and human CD40, which is important for clinical translation of2C10. To confirm the ability of 2C10 to block binding of its cognateligand, CD154, rhesus and human B cells were incubated with escalatingconcentrations of 2C10 or an isotype control and then incubated withhistidine-tagged soluble CD154 (R&D Systems, Minneapolis, Minn.) andanalyzed for histidine expression. 2C10 blocked the binding of CD154 ina dose-dependent manner (FIG. 3), indicating that 2C10 can effectivelyblock the interaction of T cell-bound CD154 with CD40 on B cells andantigen-presenting cells.

2C10 Blocks B Cell Activation in Rhesus Monkey and Human PeripheralBlood Mononuclear Cells

The CD40 antibody 2C10 was characterized with respect to its ability toaffect B cell activation both using rhesus monkey and human peripheralblood mononuclear cells (PBMCs). CD20 expression was chosen as being anindicator of B cells, and expression of CD23, CD80, and CD86 isassociated with B cell activation. 2C10 was first assessed for itsability to bind to CD20. Rhesus or human PBMCs were incubated withfluorochrome-conjugated 2C10 and an anti-CD20 antibody. Flow cytometricanalysis was used to confirm the binding of 2C10 to human and rhesusCD20+ B cells (FIG. 2A). In another set of experiments, PBMCs fromeither rhesus monkey or humans were cultured either in the presence orabsence of CD154⁺ Jurkat D1.1 cells, an immortalized T lymophocyte cellline. Activation of B cells was determined by measuring expression ofthree markers (CD23, CD80, and CD86) in CD20⁺ cells present in thePBMCs. The general scheme of this assay is shown in FIG. 4. As shown inFIG. 4, culturing PBMCs in the presence of Jurkat cells resulted inincreased expression of all three markers, indicating that B cells areactivated by the CD154⁺ Jurkat cells.

To test the ability of antibodies to block B cell activation, PBMCs andJurkat cells were co-cultured in the presence or absence of one of threeantibodies: 3A8, 5C8, and 2C10. The 3A8 antibody is a mouse anti-humanCD40 antibody (ATCC Deposit No. HB-12024), and 5C8 is an anti-CD154antibody (ATCC Deposit No. CRL-10915). Each was used as a positivecontrol. Co-cultures were conducted over a range of five orders ofmagnitude of antibody concentration (0.001 μg to 10 μg). As shown inFIG. 5, 3A8 did not block B cell activation in rhesus PBMCs, as measuredby CD23 expression, whereas both 2C10 and 5C8 were able to blockactivation with similar efficiency. Corresponding changes were alsoobserved with CD80 and CD86 expression. These results indicate that 2C10binds to a different epitope on CD40 than 3A8. These results alsoindicate that 2C10 acts primarily as a CD40 antagonist in contrast to3A8 which has previously been shown to act as partial agonists with weakstimulatory potential (Adams et al., J. Immunol. 174:542-50, 2005,Badell et al., Am. J. Transplant. accepted for publication, 2011). Whena similar experiment was performed using human, rather than rhesus,PBMCs, both 2C10 and 5C8 were again observed to block B cell activation,as measured by CD86 expression, with similar efficiency. Here, the 3A8antibody, unlike with the rhesus PBMCs, blocked B cell activation (FIG.6).

The 2C10 and 3A8 antibodies were also tested for their ability toactivate B cells in the absence of Jurkat cells using either rhesusmonkey or human PBMCs. Here, PBMCs were cultured either in the presenceor absence of either 2C10 or 3A8. Expression of CD23, CD80, and CD86 wasthen measured in CD20⁴ cells. As shown in FIG. 7, CD23 expression inrhesus cells was increased in the presence of the 3A8, but not the 2C10,antibody. By contrast, neither 3A8 nor 2C10 activated human B cells. Thedifferences in activity observed between the 3A8 and 2C10 antibodyindicate that the 2C10 antibody binds to an epitope different from thatof the 3A8 antibody.

2C10 Prevents a T Cell-dependent Antibody Response

Having established that 2C10 binds to a unique epitope on CD40, inhibitsB cell activation similarly to an anti-CD154 antibody, and lacksagonistic properties, we then characterized the effects of 2C10 in vivo.Recombinant mouse-rhesus chimeric forms of 2C10 were generated usingeither rhesus IgG1 (2C10R1) or IgG4 (2C10R4) heavy chain and rhesuskappa light chain constant region sequences. A chimeric rhesus IgG1 formof 3A8 (3A8R1) was also generated for use as a control.

Rhesus macaques were immunized once on day zero with4-hydroxy-3-nitrophenylacetyl-conjugated keyhole limpet hemocyanin (KLH,10 mg IM) antigen (Biosearch Technologies, Novato, Calif.). Prior toimmunization and at one week, cohorts of three animals received anintravenous dose (50 mg/kg) of 2C10R1, 2C10R4, 3A8R1, or saline. Allanimals were observed for 70 days, and flow cytometry was performedweekly. Treatment with either recombinant 2C10 isotypes resulted inmodest change in peripheral B cell counts (FIG. 8) compared to thepreviously reported significant and prolonged depletion of peripheral Bcells occurring in animals receiving either 3A8R1 (Badell et al., Am. J.Transplant. 10:214, 2010) or Chi220 (Adams et al., J. Immunol.174:542-50, 2005).

T cell-dependent antibody responses to KLH-NP were tested by ELISA.Plates were coated with KLH (0.01 mg/ml, Sigma, St. Louis, Mo.) andblocked with Super Block (Thermo Scientific, Woodstock, Ga.). Pre- andpost-treatment plasma samples were serially diluted, plated for 1 hr,and washed with phosphate-buffered saline/0.05% Tween. Anti-KLHantibodies were detected by incubating for 1 hr with monoclonalanti-rhesus IgG-horseradish peroxidase (clone 1B3, NHP Reagent Resource,Boston, Mass.). Plates were then incubated with Peroxidase SubstrateSolution (KPL). Stop solution (KPL) was then added, and optical densitywas read on an ELISA plate reader at 450 nm. A sample was consideredpositive at a given dilution if the optical density reading of thepost-treatment plasma exceeded the optical density of the pre-treatmentplasma at the same dilution by 2-fold. Following KLH immunization,control animals developed high-titer KLH-specific IgG (FIG. 9). Animalsthat received 3A8R1 also developed anti-KLH responses, but titers wereapproximately 10-fold lower than controls despite significant depletionof B cells. In contrast, the generation of IgG anti-KLH antibodies wasnearly completely blocked through day 56 in all animals that receivedeither 2C10R1 or 2C10R4.

2C10 Significantly Prolongs Islet Allograft Survival in a Macaque Modelof Allogeneic Islet Transplantation

We further tested 2C10R4, the CD4 purified chimeric rhesis IgG4antibody, in a nonhuman primate allogenic islet transplant model (FIG.10). Rhesus macaques weighing 10-20 kg underwent donor pancreatectomyone day prior to transplantation via a midline laparotomy. The pancreaswas isolated and placed on ice after the animals were terminallyexsanguinated. Islet isolation was performed using Collagenase/Neutralprotease (950 Wunsch units and 63 units, respectively; Serva,Heidelberg, Germany). The digested pancreas was purified on a fourlayer, discontinuous Euroficoll gradient (Mediatech, Manassas, Va.) andCobe 2991 blood cell processor (CaridianBCT, Lakewood, Colo.). Samplesof the final islet preparation were counted and expressed as isletequivalents (IEQ). Isolated islets were cultured overnight, counted andsuspended in Transplant Media (Mediatech).

Rhesus macaques weighing 3-5 kg were rendered diabetic usingstreptozotocin (1250 mg/m² IV; Zanosar, Teva Parenteral Medicines,Irvine, Calif.) four weeks prior to transplantation. Diabetes wasconfirmed by intravenous glucose tolerance test (IVGTT) with a 500 mg/kgbolus of dextrose and measurement of primate C-peptide. Glucose levelswere monitored and C-peptide was measured at baseline and 10, 30, 60 and90 after injection of dextrose. Diabetes was confirmed by measurement ofelevated blood glucose levels in the absence of detectable serumC-peptide. Diabetic recipients underwent MIIC-mismatched isletallotransplantation. A mean of 15,745 (+4,063) IEQ were infused via asmall midline laparotomy and cannulation of a mesenteric vein.

Blood glucose levels were measured twice daily by earstick; NPH(Novolin; Novo Nordisk, Princeton, N.J.) and glargine (Lantus;Sanofi-Aventis, Bridgewater, N.J.) insulin were administered to maintainfasting blood glucose (FBG) less than 300 mg/dL pre-transplant andfollowing graft rejection. IVGTT was performed periodicallypost-transplant to monitor graft function. Transplant recipientsunderwent weekly flow cytometric analysis to monitor T cell (CD3 V450,CD4 PerCP-Cy5.5, CD8 PerCp; BD Bioscience) and B cell (CD20 PE, BDBioscience) populations. After islet engraftment rejection was definedas FBG greater than 130 mg/dL on two consecutive days. Primary endpointwas rejection-free islet graft survival. All animals used in theseexperiments were treated in compliance with the Emory University IACUCand the Guide for the Care and Use of Laboratory Animals.

Transplant recipients received either 2C10R4, basiliximab (Simulect,Novartis, Basel, Switzerland) and sirolimus, or basiliximab andsirolimus alone. 2C10R4 (50 mg/kg) was administered intravenously onpost-operative day (POD) 0 and 7. Basiliximab (0.3 mg/kg) wasadministered intravenously on POD 0 and 3. Sirolimus was administeredintramuscularly daily to achieve trough levels of 5-15 ng/ml through POD120. All three animals receiving basiliximab and sirolimus alone arehistoric controls (Badell et al., J. Clin. Invest. 120:4520-312, 2010).Two of these historic controls (RQz6 and RIb7) underwent diabetesinduction by pancreatectomy and received oral sirolimus.

Treatment with the regimens described above resulted in significantlyprolonged islet graft survival (FIG. 11A) compared to controls receivingonly basiliximab induction and sirolimus maintenance therapy (FIG. 11B).Median rejection-free graft survival time for animals receiving 2C10R4is 280 days compared to 8 days for control animals (p=0.010, Table 1).Pharmacokinetic data predict that plasma 2C10R4 levels would be lessthan 1 μg/ml by POD 100. Because sirolimus was discontinued at POD120,the recipient with the longest survival (304 days) received noimmunosuppression for approximately 24 weeks prior to rejection. Noanimals treated with 2C10R4 developed clinically relevant infectiouscomplications or weight loss. These results reflect animals thatreceived the IgG4 isotype of 2C10. Two additional animals that receivedthe IgG1 isotype of 2C10 (2C10R1) in combination with basiliximab andsirolimus achieved similarly prolonged graft survival of 220 and 162days (data not shown). Given the positive results with 2C10 used asinduction therapy, the next step is to assess the effects on graftsurvival by administering 2C10 as maintenance therapy.

TABLE 1 Graft Survival Recipient Therapy IEQ/kg (days) Comment DP4A2C10R4/Basiliximab/ 21,973 296 Rejection Sirolimus RAo132C10R4/Basiliximab/ 14,388 304 Rejection Sirolimus RZq132C10R4/Basiliximab/ 15,881 265 Rejection Sirolimus RRq132C10R4/Basiliximab/ 20,596 163 Rejection Sirolimus RQz6Basiliximab/Sirolimus 12,980 8 Rejection Rlb7 Basiliximab/Sirolimus10,903 8 Rejection RMc11 Basiliximab/Sirolimus 13,796 10 RejectionBlockade of the CD40/CD154 Pathway in Conjunction with the CD28/B7Pathway

Blockade of the CD40/CD154 pathway may prove useful in conjunction withother costimulation blockade agents. Belatacept, a high affinity versionof CTLA4-Ig designed to block the CD28/B7 costimulatory pathways, hasshown efficacy in nonhuman primate models of renal and islettransplantation and in phase II and III clinical trials in renaltransplantation (Larsen et al., Transplantation 90:1528-35, 2010,Vincenti et al., Am. J. Transplant. 10:535-46, 2010, Adams et al., J.Immunol. 174:542-50, 2005, Adams et al., Diabetes 51:265-70, 2002,Larsen et al., Am. J. Transplant. 5:443-53, 2005, Vincenti et al., N.Engl. J. Med. 358:770-81, 2005). The BENEFIT trial revealed superiorrenal function in patients treated with belatacept; however, thesepatients had a higher incidence and more severe grade of biopsy-provenacute rejection (Larsen et al., Transplantation 90:1528-35, 2010,Vincenti et al. Am. J. Transplant. 10:535-46, 2010). In light of thisincreased rate of acute rejection and the synergy between CD40 and B7blockade (Larsen et al., Nature 381:434-8, 1996), we next want to testthe efficacy of combined 2C10 and belatacept therapy in nonhuman primatekidney transplantation.

Epitope Mapping

Methods for identifying the particular epitope to which an antibodybinds are known to those skilled in the art. Standard techniques includepeptide scanning, in which overlapping, short peptides (for example,10-30 amino acids, e.g., 20, in length) derived from the full lengthprotein to which the antibody binds are individually tested for theirability to bind the antibody. From such experiments, the region of theprotein to which the antibody binds can then be determined.

Site-directed mutagenesis can also be used to identify the antigenicregion(s) of a particular protein. In this approach, point mutations aresystematically introduced into the target polypeptide and the ability ofthe antibody to bind the peptide with mutations at various positions isused to determine whether a particular region of that protein containsthe epitope to which the antibody binds.

Antibody epitopes can also be identified using high-through mutagenesistechniques, such as Shotgun Mutagenesis (Integral Molecular, Inc.,Philadelphia, Pa.), which can be used to generate large numbers ofmutations within the target protein. Such methodologies permit efficientidentification of eptitopes within the protein.

To determine if various antibodies to CD40 bind similar epitopes, an invitro competitive blockade assay was performed. The antibodies 2C10, 3A8and Chi220, a chimeric IgG1 CD40-specific antibody, were used in theassay. 2C10 was conjugated to allophycocyanin (APC) using the LightningLink antibody labeling kit (Novus Biologics, Littleton, Colo.). HumanPBMCs were incubated with escalating concentrations of 2C10, 3A8, orChi220, and then stained with the APT-conjugated 2C10 to assess theability of each antibody to cross-block 2C10. Binding of APC-conjugated2C10 decreased with increasing concentrations of 2C10 but not Chi220 or3A8 as shown in FIG. 12. The result indicates that 2C10 binds a uniqueepitope distinct from either Chi220 or 3A8.

Generation of Additional Antibodies

Additional antibodies (e.g., monoclonal, polyclonal, poly-specific, ormono-specific antibodies) against the CD40 epitope recognized by 2C10can be made, e.g., using any of the numerous methods for makingantibodies known in the art. In one example, a coding sequence for aneptiope recognized by the 2C10 antibody is expressed as a C-terminalfusion with glutathione S-transferase (GST) (Smith et al., Gene67:31-40, 1988). The fusion protein is purified on glutathione-Sepharosebeads, eluted with glutathione, cleaved with thrombin (at an engineeredcleavage site), and purified for immunization of rabbits. Primaryimmunizations are carried out with Freund's complete adjuvant andsubsequent immunizations with Freund's incomplete adjuvant. Antibodytiters are monitored by Western blot and immunoprecipitation analysesusing the thrombin-cleaved protein fragment of the GST fusion protein.Immune sera are affinity purified using CNBr-Sepharose-coupled protein.Antiserum specificity can be determined using a panel of unrelated GSTproteins.

As an alternate or adjunct immunogen to GST fusion proteins, peptidescorresponding to relatively unique immunogenic regions of a polypeptideof the invention can be generated and coupled to keyhole limpethemocyanin (KLH) through an introduced C-terminal lysine. Antiserum toeach of these peptides is similarly affinity purified on peptidesconjugated to BSA, and specificity is tested by ELISA or Western blotanalysis using peptide conjugates, or by Western blot orimmunoprecipitation using the polypeptide expressed as a GST fusionprotein.

Alternatively, monoclonal antibodies that specifically bind the CD40eptiope recognized the 2C10 antibody can be prepared using standardhybridoma technology (see, e.g., Kohler et al., Nature 256:495-7, 1975;Kohler et al., Eur. J. Immuno. 6:511-9, 1976; Kohler et al., Eur. J.Immunol. 6:292-5, 1976; Hammerling et al., Monoclonal Antibodies and TCell Hybridomas, Elsevier, N Y, 1981). Once produced, monoclonalantibodies can also be tested for specific recognition by Western blotor immunoprecipitation analysis. Alternatively, monoclonal antibodiescan be prepared using the polypeptide of the invention described aboveand a phage display library (Vaughan et al., Nat. Biotechnol. 14:309-14,1996).

Epitopic fragments can be generated by standard techniques, e.g., usingPCR and cloning the fragment into a pGEX expression vector. Fusionproteins are expressed in E. coli and purified using a glutathioneagarose affinity matrix. To minimize potential problems of low affinityor specificity of antisera, two or three such fusions are generated foreach protein, and each fusion is injected into at least two rabbits.Antisera are raised by injections in a series, and can include, forexample, at least three booster injections.

In order to generate polyclonal antibodies on a large scale and at a lowcost an appropriate animal species can be chosen. Polyclonal antibodiescan be isolated from the milk or colostrum of, e.g., immunized cows.Bovine colostrum contains 28 g of IgG per liter, while bovine milkcontains 1.5 g of IgG per liter (Ontsouka et al., J. Dairy Sci.86:2005-11, 2003). Polyclonal antibodies can also be isolated from theyolk of eggs from immunized chickens (Sarker et al., J. Pediatr.Gastroenterol. Nutr. 32:19-25, 2001).

Multiple adjuvants are approved for use in dairy cows. Adjuvants usefulin this invention include, but are not limited to, Emulsigen®, anoil-in-water emulsified adjuvant, Emulsigen®-D, an oil-in-wateremulsified adjuvant with DDA immunostimulant, Emulsigen®-P, anoil-in-water emulsified adjuvant with co-polymer immunostimulant,Emulsigen®-BCL, an oil-in-water emulsified adjuvant with blockco-polymer immunostimulant, Carbigen™, a carbomer base, and Polygen™, aco-polymer base. All of the listed adjuvants are commercially availablefrom MVP Laboratories in Omaha, Nebr.

Useful antibodies can be identified in several different screeningassays. First, antibodies are assayed by ELISA to determine whether theyare specific for the immunizing antigen (i.e., the CD40 epitopedescribed herein). Using standard techniques, ELISA plates are coatedwith immunogen, the antibody is added to the plate, washed, and thepresence of bound antibody detected by using a second antibody specificfor the Ig of the species in which the antibody was generated.

A functional in vitro assay can be used to screen antibodies e.g., anneutralizing assay based on monocyte-derived dendritic cells.

Direct measurements of bovine immunoglobulin in illeal fluid in humansubjects have shown that significant amounts of immunoglobulin survivetransit through the stomach and small intestine (Warny et al., Gut44:212-7, 1999). Methods have also been described to formulate avianimmunoglobulin (IgY) for GI delivery (Kovacs-Nolan et al., Immunol.Methods 296:199-209, 2005).

Humanized Antibodies

The invention encompasses humanized antibodies. Various methods forhumanizing non-human antibodies are known in the art. For example, ahumanized antibody can have one or more amino acid residues introducedinto it from a source which is non-human. These non-human amino acidresidues are often referred to as “import” residues, which are typicallytaken from an “import” variable domain. Humanization can be essentiallyperformed following the method of Winter and co-workers (Jones et al.,Nature 321:522-5, 1986; Riechmann et al., Nature 332:323-7, 1988;Verhoeyen et al., Science 239:1534-6, 1988), by substitutinghypervariable region sequences for the corresponding sequences of ahuman antibody. Accordingly, such “humanized” antibodies are chimericantibodies (U.S. Pat. No. 4,816,567), where substantially less than anintact human variable domain has been substituted by the correspondingsequence from a non-human species. In practice, humanized antibodies aretypically human antibodies in which at least some hypervariable regionresidues as well as other variable region residues are substituted byresidues from analogous sites in rodent antibodies.

The choice of human variable domains, both light and heavy, to be usedin making the humanized antibodies can be important to reduceantigenicity. According to the so-called “best-fit” method, the sequenceof the variable domain of a rodent antibody is screened against theentire library of known human variable-domain sequences. The humansequence which is closest to that of the rodent is then accepted as thehuman framework for the humanized antibody. See, e.g., Sims et al., J.Immunol. 151:2296-308, 1993; Chothia et al., J. Mol. Biol. 196:901-17,1987. Another method uses a particular framework derived from theconsensus sequence of all human antibodies of a particular subgroup oflight or heavy chains. The same framework may be used for severaldifferent humanized antibodies. See, e.g., Carter et al., Proc. Natl.Acad. Sci. USA 89:4285-9, 1992; Presta et al., J. Immunol. 151:2623-32,1993.

It is further generally desirable that antibodies be humanized withretention of high affinity for the antigen and other favorablebiological properties. To achieve this goal, according to one method,humanized antibodies are prepared by a process of analysis of theparental sequences and various conceptual humanized products usingthree-dimensional models of the parental and humanized sequences.Three-dimensional immunoglobulin models are commonly available and arefamiliar to those skilled in the art. Computer programs are availablewhich illustrate and display probable three-dimensional conformationalstructures of selected candidate immunoglobulin sequences. Inspection ofthese displays permits analysis of the likely role of the residues inthe functioning of the candidate immunoglobulin sequence, i.e., theanalysis of residues that influence the ability of the candidateimmunoglobulin to bind its antigen. In this way, FR residues can beselected and combined from the recipient and import sequences so thatthe desired antibody characteristic, such as increased affinity for thetarget antigen(s), is achieved. In general, the hypervariable regionresidues are directly and most substantially involved in influencingantigen binding.

Human Antibodies

Human antibodies of the invention can be constructed by combining Fvclone variable domain sequence(s) selected from human-derived phagedisplay libraries with known human constant domain sequences(s)(Hoogenboom et al., J. Mol. Biol. 227:381-8, 1992; Marks et al., J. Mol.Biol. 222:581-97, 1991). Alternatively, human monoclonal antibodies ofthe invention can be made by the hybridoma method. Human myeloma andmouse-human heteromyeloma cell lines for the production of humanmonoclonal antibodies have been described, for example, by Kozbor, J.Immunol. 133:3001-5, 1984; Brodeur et al., Monoclonal AntibodyProduction Techniques and Applications, pp. 51-63 (Marcel Dekker, Inc.,New York, 1987); and Boerner et al., J. Immunol. 147: 86-95, 1991.

It is now possible to produce transgenic animals (e.g., mice) that arecapable, upon immunization, of producing a full repertoire of humanantibodies in the absence of endogenous immunoglobulin production. Forexample, it has been described that the homozygous deletion of theantibody heavy-chain joining region (JH) gene in chimeric and germ-linemutant mice results in complete inhibition of endogenous antibodyproduction. Transfer of the human germ-line immunoglobulin gene array insuch germ-line mutant mice will result in the production of humanantibodies upon antigen challenge. See, e.g., Jakobovits et al., Proc.Natl. Acad. Sci. USA 90:2551-5, 1993; Jakobovits et al., Nature362:255-8, 1993; Brüggemann et al., Year Immunol. 7:33-40, 1993.

Gene shuffling can also be used to derive human antibodies fromnon-human, e.g., rodent, antibodies, where the human antibody hassimilar affinities and specificities to the starting non-human antibody.According to this method, which is also called “epitope imprinting,”either the heavy or light chain variable-region of a non-human antibodyfragment obtained by phage display techniques as described herein isreplaced with a repertoire of human V domain genes, creating apopulation of non-human chain/human chain scFv or Fab chimeras.Selection with antigen results in isolation of a non-human chain/humanchain chimeric scFv or Fab where the human chain restores the antigenbinding site destroyed upon removal of the corresponding non-human chainin the primary phage display clone, i.e., the epitope governs (imprints)the choice of the human chain partner. When the process is repeated inorder to replace the remaining non-human chain, a human antibody isobtained (see PCT Publication WO 93/06213). Unlike traditionalhumanization of non-human antibodies by CDR grafting, this techniqueprovides completely human antibodies, which have no FR or CDR residuesof non-human origin.

Antibody Fragments

The invention also features antibody fragments that comprise a portionof an intact antibody, preferably comprising the antigen binding regionthereof. Examples of antibody fragments include Fab, Fab′, F(ab′)₂, andFv fragments; diabodies; linear antibodies; single-chain antibodymolecules; and multispecific antibodies formed from antibody fragments.

Papain digestion of antibodies produces two identical antigen-bindingfragments, called “Fab” fragments, each with a single antigen-bindingsite, and a residual “Fc” fragment, whose name reflects its ability tocrystallize readily. Pepsin treatment yields an F(ab′)₂ fragment thathas two antigen-combining sites and is still capable of cross-linkingantigen.

Fv is the minimum antibody fragment which contains a completeantigen-binding site. In one embodiment, a two-chain Fv species consistsof a dimer of one heavy- and one light-chain variable domain in tight,non-covalent association. In a single-chain Fv (scFv) species, oneheavy- and one light-chain variable domain can be covalently linked by aflexible peptide linker such that the light and heavy chains canassociate in a “dimeric” structure analogous to that in a two-chain Fvspecies. It is in this configuration that the three hypervariableregions (HVRs) of each variable domain interact to define anantigen-binding site on the surface of the VH-VL dimer. Collectively,the six HVRs confer antigen-binding specificity to the antibody.However, even a single variable domain (or half of an Fv comprising onlythree HVRs specific for an antigen) has the ability to recognize andbind antigen, although at a lower affinity than the entire binding site.

The Fab fragment contains the heavy- and light-chain variable domainsand also contains the constant domain of the light chain and the firstconstant domain (CH1) of the heavy chain. Fab′ fragments differ from Fabfragments by the addition of a few residues at the carboxy terminus ofthe heavy chain CH1 domain including one or more cysteines from theantibody hinge region. Fab′-SH is the designation herein for Fab′ inwhich the cysteine residue(s) of the constant domains bear a free thiolgroup. F(ab′)₂ antibody fragments originally were produced as pairs ofFab′ fragments which have hinge cysteines between them. Other chemicalcouplings of antibody fragments are also known.

Single-chain Fv or scFv antibody fragments comprise the V_(H) and V_(L)domains of antibody, where these domains are present in a singlepolypeptide chain. Generally, the scFv polypeptide further comprises apolypeptide linker between the V_(H) and V_(L) domains which enables thescFv to form the desired structure for antigen binding. For a review ofscFv, see, e.g., Pluckthün, in The Pharmacology of MonoclonalAntibodies, vol. 113, Rosenburg and Moore eds., (Springer-Verlag, NewYork, 1994), pp. 269-315.

Diabodies are antibody fragments with two antigen-binding sites, whichfragments comprise a heavy-chain variable domain (V_(H)) connected to alight-chain variable domain (V_(L)) in the same polypeptide chain(V_(H)-V_(L)). By using a linker that is too short to allow pairingbetween the two domains on the same chain, the domains are forced topair with the complementary domains of another chain and create twoantigen-binding sites. Diabodies may be bivalent or bispecific.Diabodies are described more fully in, for example, European Patent No.404,097; PCT Publication WO 1993/01161; Hudson et al., Nat. Med.9:129-34, 2003; and Hollinger et al., Proc. Natl. Acad. Sci. USA90:6444-8, 1993. Triabodies and tetrabodies are also described in Hudsonet al., Nat. Med. 9:129-34, 2003.

Antibody fragments may be generated by traditional means, such asenzymatic digestion, or by recombinant techniques. In certaincircumstances there are advantages of using antibody fragments, ratherthan whole antibodies. The smaller size of the fragments allows forrapid clearance, and may lead to improved access to solid tumors. For areview of certain antibody fragments, see Hudson et al. Nat. Med.9:129-134, 2003.

Various techniques have been developed for the production of antibodyfragments. Traditionally, these fragments were derived via proteolyticdigestion of intact antibodies (see, e.g., Morimoto et al., J. Biochem.Biophys. Methods 24:107-17, 1992; and Brennan et al., Science 229:81-3,1985). However, these fragments can now be produced directly byrecombinant host cells. Fab, Fv, and ScFv antibody fragments can all beexpressed in and secreted from E. coli, thus allowing the facileproduction of large amounts of these fragments. Antibody fragments canbe isolated from the antibody phage libraries. Alternatively, Fab′-SHfragments can be directly recovered from E. coli and chemically coupledto form F(ab′)₂ fragments (Carter et al., Bio/Technology 10:163-7,1992). In another approach, F(ab′)₂ fragments are isolated directly fromrecombinant host cell culture. Fab and F(ab′)₂ fragment with increasedin vivo half-life comprising salvage receptor binding epitope residuesare described in U.S. Pat. No. 5,869,046. Other techniques for theproduction of antibody fragments will be apparent to the skilledpractitioner.

Pharmaceutical Compositions

The present invention provides a composition, e.g., a pharmaceuticalcomposition, containing an antibody, or antigen-binding portion(s)thereof, of the present invention, formulated together with apharmaceutically acceptable carrier. Pharmaceutical compositions of theinvention also can be administered in combination therapy, i.e.,combined with other agents (e.g., immunosuppressants). As used herein,“pharmaceutically acceptable carrier” includes any and all solvents,dispersion media, coatings, antibacterial and antifungal agents,isotonic and absorption delaying agents, and the like that arephysiologically compatible. Preferably, the carrier is suitable forintravenous, intrathecal, intramuscular, subcutaneous, parenteral,spinal or epidermal administration (e.g., by injection or infusion).Depending on the route of administration, the antibodies of theinvention may be coated in a material to protect the compound from theaction of acids and other natural conditions that may inactivate thecompound.

A composition of the present invention can be administered by a varietyof methods known in the art. As will be appreciated by the skilledartisan, the route and/or mode of administration will vary dependingupon the desired results. Administration may be parenteral, intravenous,intrathecal, subcutaneous, oral, topical, or local, for example, bydirect injection into the cerebrospinal fluid. Intravenous delivery bycontinuous infusion is one exemplary method for administering thetherapeutic antibodies of the present invention. The therapeuticcompound may be in the form of a solution; a suspension, an emulsion, aninfusion device, or a delivery device for implantation, or it may bepresented as a dry powder to be reconstituted with water or anothersuitable vehicle before use. The composition can be in the form of apill, tablet, capsule, liquid, or sustained release tablet for oraladministration; or a liquid for intravenous, intrathecal, subcutaneousor parenteral administration; or a polymer or other sustained releasevehicle for local administration.

Methods well known in the art for making formulations are found, forexample, in “Remington: The Science and Practice of Pharmacy” (20th ed.,ed. A. R. Gennaro Ark., 2000, Lippincott Williams & Wilkins,Philadelphia, Pa.). Formulations for parenteral administration may, forexample, contain excipients, sterile water, saline, polyalkylene glycolssuch as polyethylene glycol, oils of vegetable origin, or hydrogenatednapthalenes. Biocompatible, biodegradable lactide polymer,lactide/glycolide copolymer, or polyoxyethylene-polyoxypropylenecopolymers may be used to control the release of the compounds.Nanoparticulate formulations (e.g., biodegradable nanoparticles, solidlipid nanoparticles, liposomes) may be used to control thebiodistribution of the compounds. Other potentially useful deliverysystems include ethylene-vinyl acetate copolymer particles, osmoticpumps, intrathecal pumps, implantable infusion systems, and liposomes.The concentration of the compound in the formulation varies dependingupon a number of factors, including the dosage of the drug to beadministered, and the route of administration.

To administer a compound of the invention by certain routes ofadministration, it may be necessary to coat the compound with, orco-administer the compound with, a material to prevent its inactivation.For example, the compound may be administered to a subject in anappropriate carrier, for example, liposomes, or a diluent.Pharmaceutically acceptable diluents include saline and aqueous buffersolutions. Liposomes include water-in-oil-in-water CGF emulsions as wellas conventional liposomes (Strejan et al., J. Neuroimmunol. 7:27-41,1984). Pharmaceutically acceptable carriers include sterile aqueoussolutions or dispersions and sterile powders for the extemporaneouspreparation of sterile injectable solutions or dispersion. The use ofsuch media and agents for pharmaceutically active substances is known inthe art and is included in the invention except where any conventionalmedia or agent is incompatible with the active compound. Supplementaryactive compounds can also be incorporated into the compositions.

Therapeutic compositions typically must be sterile and stable under theconditions of manufacture and storage. The composition can be formulatedas a solution, microemulsion, liposome, or other ordered structuresuitable to high drug concentration. The carrier can be a solvent ordispersion medium containing, for example, water, ethanol, polyol (forexample, glycerol, propylene glycol, and liquid polyethylene glycol, andthe like), and suitable mixtures thereof. The proper fluidity can bemaintained, for example, by the use of a coating such as lecithin, bythe maintenance of the required particle size in the case of dispersionand by the use of surfactants. In many cases, it will be preferable toinclude isotonic agents, for example, sugars, polyalcohols such asmannitol, sorbitol, or sodium chloride in the composition. Prolongedabsorption of the injectable compositions can be brought about byincluding in the composition an agent that delays absorption, forexample, monostearate salts and gelatin.

Sterile injectable solutions can be prepared by incorporating the activecompound in the required amount in an appropriate solvent with one or acombination of ingredients enumerated above, as required, followed bysterilization microfiltration. Generally, dispersions are prepared byincorporating the active compound into a sterile vehicle that contains abasic dispersion medium and the required other ingredients from thoseenumerated above. In the case of sterile powders for the preparation ofsterile injectable solutions, the preferred methods of preparation arevacuum drying and freeze-drying (lyophilization) that yield a powder ofthe active ingredient plus any additional desired ingredient from apreviously sterile-filtered solution thereof. Dosage regimens areadjusted to provide the optimum desired response (e.g., a therapeuticresponse). For example, a single bolus may be administered, severaldivided doses may be administered over time or the dose may beproportionally reduced or increased as indicated by the exigencies ofthe therapeutic situation. For example, the antibodies of the inventionmay be administered once or twice weekly by subcutaneous injection oronce or twice monthly by subcutaneous injection.

It is especially advantageous to formulate parenteral compositions indosage unit form for ease of administration and uniformity of dosage.Dosage unit form as used herein refers to physically discrete unitssuited as unitary dosages for the subjects to be treated; each unitcontains a predetermined quantity of active compound calculated toproduce the desired therapeutic effect in association with the requiredpharmaceutical carrier. The specification for the dosage unit forms ofthe invention are dictated by and directly dependent on (a) the uniquecharacteristics of the active compound and the particular therapeuticeffect to be achieved, and (b) the limitations inherent in the art ofcompounding such an active compound for the treatment of sensitivity inindividuals.

The phrases “parenteral administration” and “administered parenterally”as used herein mean modes of administration other than enteral andtopical administration, usually by injection, and include, withoutlimitation, intravenous, intramuscular, intraarterial, intrathecal,intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal,transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular,subarachnoid, intraspinal, epidural and intrasternal injection andinfusion. Examples of suitable aqueous and nonaqueous carriers which maybe employed in the pharmaceutical compositions of the invention includewater, ethanol, polyols (such as glycerol, propylene glycol,polyethylene glycol, and the like), and suitable mixtures thereof,vegetable oils, such as olive oil, and injectable organic esters, suchas ethyl oleate. Proper fluidity can be maintained, for example, by theuse of coating materials, such as lecithin, by the maintenance of therequired particle size in the case of dispersions, and by the use ofsurfactants.

Compositions of the invention may also contain adjuvants such aspreservatives, wetting agents, emulsifying agents and dispersing agents.Prevention of presence of microorganisms may be ensured both bysterilization procedures, and by the inclusion of various antibacterialand antifungal agents, for example, paraben, chlorobutanol, phenolsorbic acid, and the like. It may also be desirable to include isotonicagents, such as sugars, sodium chloride, and the like into thecompositions. In addition, prolonged absorption of the injectablepharmaceutical form may be brought about by the inclusion of agentswhich delay absorption such as aluminum monostearate and gelatin. Whenthe compounds of the present invention are administered aspharmaceuticals, to humans and animals, they can be given alone or as apharmaceutical composition containing, for example, 0.001 to 90% (morepreferably, 0.005 to 70%, such as 0.01 to 30%) of active ingredient incombination with a pharmaceutically acceptable carrier.

For intravenous or intrathecal delivery or direct injection, thecomposition must be sterile and fluid to the extent that the compositionis deliverable by syringe. In addition to water, the carrier can be anisotonic buffered saline solution, ethanol, polyol (for example,glycerol, propylene glycol, and liquid polyetheylene glycol, and thelike), and suitable mixtures thereof. Proper fluidity can be maintained,for example, by use of coating such as lecithin, by maintenance ofrequired particle size in the case of dispersion and by use ofsurfactants. In many cases, it is preferable to include isotonic agents,for example, sugars, polyalcohols such as mannitol or sorbitol, andsodium chloride in the composition. Long-term absorption of theinjectable compositions can be brought about by including in thecomposition an agent which delays absorption, for example, aluminummonostearate or gelatin.

Regardless of the route of administration selected, the compounds of thepresent invention, which may be used in a suitable hydrated form, and/orthe pharmaceutical compositions of the present invention, are formulatedinto pharmaceutically acceptable dosage forms by conventional methodsknown to those of skill in the art. Actual dosage levels of the activeingredients in the pharmaceutical compositions of the present inventionmay be varied so as to obtain an amount of the active ingredient whichis effective to achieve the desired therapeutic response for aparticular patient, composition, and mode of administration, withoutbeing toxic to the patient. The selected dosage level will depend upon avariety of pharmacokinetic factors including the activity of theparticular compositions of the present invention employed, or the ester,salt or amide thereof, the route of administration, the time ofadministration, the rate of excretion of the particular compound beingemployed, the duration of the treatment, other drugs, compounds and/ormaterials used in combination with the particular compositions employed,the age, sex, weight, condition, general health and prior medicalhistory of the patient being treated, and like factors well known in themedical arts. A physician or veterinarian having ordinary skill in theart can readily determine and prescribe the effective amount of thepharmaceutical composition required. For example, the physician orveterinarian can start doses of the compounds of the invention employedin the pharmaceutical composition at levels lower than that required inorder to achieve the desired therapeutic effect and gradually increasethe dosage until the desired effect is achieved. In general, a suitabledaily dose of a composition of the invention will be that amount of thecompound which is the lowest dose effective to produce a therapeuticeffect. Such an effective dose will generally depend upon the factorsdescribed above. If desired, the effective daily dose of a therapeuticcomposition may be administered as two, three, four, five, six or moresub-doses administered separately at appropriate intervals throughoutthe day, optionally, in unit dosage forms. While it is possible for acompound of the present invention to be administered alone, it ispreferable to administer the compound as a pharmaceutical formulation(composition).

Therapeutic compositions can be administered with medical devices knownin the art. Examples of well-known implants, delivery systems, andmodules useful in the present invention are known to those skilled inthe art.

Conditions and Disorders

The antibodies and antibody fragments described herein may be used inany situation in which immunosuppression is desired (e.g., transplantrejection or autoimune disorders). These antibodies are particularlyuseful for treating transplant rejection, e.g., reducing the likelihoodthat a particular transplant is rejected by the host or increasing thetime before rejection takes place. The antibodies described herein canbe used in conjunction with transplantation of any organ or any tissuethat is suitable for transplantation. Exemplary organs include heart,kidney, lung, liver, pancreas, intestine, and thymus; exemplary tissuesinclude bone, tendon, cornea, skin, heart valve, vein, and bone marrow.

The antibodies and antibody fragments can also be used to treatautoimmune disorders, particular disorders where autoantibodies areimplicated in the pathogenesis of the disease. Autoimmune diseases thatare or can be associated with autoantibody production include systemiclupus erythematosus (SLE), CREST syndrome (calcinosis, Raynaud'ssyndrome, esophageal dysmotility, sclerodactyl, and telangiectasia),opsoclonus, inflammatory myopathy (e.g., polymyositis, dermatomyositis,and inclusion-body myositis), systemic scleroderma, primary biliarycirrhosis, celiac disease (e.g., gluten sensitive enteropathy),dermatitis herpetiformis, Miller-Fisher Syndrome, acute motor axonalneuropathy (AMAN), multifocal motor neuropathy with conduction block,autoimmune hepatitis, antiphospholipid syndrome, Wegener'sgranulomatosis, microscopic polyangiitis, Churg-Strauss syndrome,rheumatoid arthritis, chronic autoimmune hepatitis, scleromyositis,myasthenia gravis, Lambert-Eaton myasthenic syndrome, Hashimoto'sthyroiditis, Graves' disease, Paraneoplastic cerebellar degeneration,Stiff person syndrome, limbic encephalitis, Isaacs Syndrome, Sydenham'schorea, pediatric autoimmune neuropsychiatric disease associated withStreptococcus (PANDAS), encephalitis, diabetes mellitus type 1, andNeuromyelitis optica.

Other autoimmune disorders include pernicious anemia, Addison's disease,psoriasis, inflammatory bowel disease, psoriatic arthritis, Sjögren'ssyndrome, lupus erythematosus (e.g., discoid lupus erythematosus,drug-induced lupus erythematosus, and neonatal lupus erythematosus),multiple sclerosis, and reactive arthritis.

Additional disorders that may be treated using the methods of thepresent invention include, for example, polymyositis, dermatomyositis,multiple endocrine failure, Schmidt's syndrome, autoimmune uveitis,adrenalitis, thyroiditis, autoimmune thyroid disease, gastric atrophy,chronic hepatitis, lupoid hepatitis, atherosclerosis, preseniledementia, demyelinating diseases, subacute cutaneous lupuserythematosus, hypoparathyroidism, Dressler's syndrome, autoimmunethrombocytopenia, idiopathic thrombocytopenic purpura, hemolytic anemia,pemphigus vulgaris, pemphigus, alopecia arcata, pemphigoid, scleroderma,progressive systemic sclerosis, adult onset diabetes mellitus (e.g.,type II diabetes), male and female autoimmune infertility, ankylosingspondolytis, ulcerative colitis, Crohn's disease, mixed connectivetissue disease, polyarteritis nedosa, systemic necrotizing vasculitis,juvenile onset rheumatoid arthritis, glomerulonephritis, atopicdermatitis, atopic rhinitis, Goodpasture's syndrome, Chagas' disease,sarcoidosis, rheumatic fever, asthma, recurrent abortion,anti-phospholipid syndrome, farmer's lung, erythema multiforme, postcardiotomy syndrome, Cushing's syndrome, autoimmune chronic activehepatitis, bird-fancier's lung, allergic disease, allergicencephalomyelitis, toxic epidermal necrolysis, alopecia, Alport'ssyndrome, alveolitis, allergic alveolitis, fibrosing alveolitis,interstitial lung disease, erythema nodosum, pyoderma gangrenosum,transfusion reaction, leprosy, malaria, leishmaniasis, trypanosomiasis,Takayasu's arteritis, polymyalgia rheumatica, temporal arteritis,schistosomiasis, giant cell arteritis, ascariasis, aspergillosis,Sampter's syndrome, eczema, lymphomatoid granulomatosis, Behcet'sdisease, Caplan's syndrome, Kawasaki's disease, dengue, endocarditis,endomyocardial fibrosis, endophthalmitis, erythema elevatum et diutinum,erythroblastosis fetalis, eosinophilic faciitis, Shulman's syndrome,Felty's syndrome, filariasis, cyclitis, chronic cyclitis, heterochroniccyclitis, Fuch's cyclitis, IgA nephropathy, Henoch-Schonlein purpura,graft versus host disease, transplantation rejection, humanimmunodeficiency virus infection, echovirus infection, cardiomyopathy,Alzheimer's disease, parvovirus infection, rubella virus infection, postvaccination syndromes, congenital rubella infection, Hodgkin's andnon-Hodgkin's lymphoma, renal cell carcinoma, multiple myeloma,Eaton-Lambert syndrome, relapsing polychondritis, malignant melanoma,cryoglobulinemia, Waldenstrom's macroglobulemia, Epstein-Barr virusinfection, mumps, Evan's syndrome, and autoimmune gonadal failure.

Immunosuppressants

The antibodies and antibody fragments described herein can be formulatedor administered in combination with an immunosuppressant. Examples ofimmunosuppressants include, but are not limited to, calcineurininhibitors (e.g., cyclosporin A (Sandimmune®), cyclosporine G tacrolimus(Prograf®, Protopic®)), mTor inhibitors (e.g., sirolimus (Rapamune®,Neoral®), temsirolimus (Torisel®), zotarolimus, and everolimus(Certican®)), fingolimod (Gilenya™), myriocin, alemtuzumab (Campath®,MabCampath®, Campath-1H®), rituximab (Rituxan®, MabThera®), an anti-CD4monoclonal antibody (e.g., HuMax-CD4), an anti-LFA1 monoclonal antibody(e.g., CD11a), an anti-LFA3 monoclonal antibody, an anti-CD45 antibody(e.g., an anti-CD45RB antibody), an anti-CD19 antibody (see, e.g., U.S.Patent Publication 2006/0280738), monabatacept (Orencia®), belatacept,indolyl-ASC (32-indole ether derivatives of tacrolimus and ascomycin),azathioprine (Azasan®, Imuran®), lymphocyte immune globulin andanti-thymocyte globulin [equine] (Atgam®), mycophenolate mofetil(Cellcept®), mycophenolate sodium (Myfortic®), daclizumab (Zenapax®),basiliximab (Simulect®), cyclophosphamide (Endoxan®, Cytoxan®, Neosar™,Procytox™, Revimmune™), prednisone, prednisolone, leflunomide (Arava®),FK778, FK779, 15-deoxyspergualin (DSG), busulfan (Myleran®, Busulfex®),fludarabine (Fludara®), methotrexate (Rheumatrex®, Trexall®),6-mercaptopurine (Purinethol®), 15-deoxyspergualin (Gusperimus),LF15-0195, bredinin, brequinar, and muromonab-CD3 (Orthoclone®).

Methods for assessing immunosuppressive activity of an agent are knownin the art. For example, the length of the survival time of thetransplanted organ in vivo with and without pharmacological interventionserves as a quantitative measure for the suppression of the immuneresponse. In vitro assays may also be used, for example, a mixedlymphocyte reaction (MLR) assay (see, e.g., Fathman et al., J. Immunol.118:1232-8, 1977); a CD3 assay (specific activation of immune cells viaan anti-CD3 antibody (e.g., OKT3)) (see, e.g., Khanna et al.,Transplantation 67:882-9, 1999; Khanna et al. (1999) Transplantation67:S58); and an IL-2R assay (specific activation of immune cells withthe exogenously added cytokine IL-2) (see, e.g., Farrar et al., J.Immunol. 126:1120-5, 1981).

Cyclosporine A (CsA; CAS No. 59865-13-3; U.S. Pat. No. 3,737,433) andits analogs may be used as an immunosuppressant. A number of othercyclosporines and their derivatives and analogs that exhibitimmunosuppressive activity are known. Cyclosporines and theirformulations are described, for example, in 2004 Physicians' DeskReference® (2003) Thomson Healthcare, 58th ed., and U.S. Pat. Nos.5,766,629; 5,827,822; 4,220,641; 4,639,434; 4,289,851; 4,384,996;5,047,396; 4,388,307; 4,970,076; 4,990,337; 4,822,618; 4,576,284;5,120,710; and 4,894,235.

Tacrolimus (FK506) is a macrolide which exerts effects largely similarto CsA, both with regard to its molecular mode of action and itsclinical efficacy (Liu, Immunol. Today 14:290-5, 1993; Schreiber et al.,Immunol. Today, 13:136-42, 1992); however, these effects are exhibitedat doses that are 20 to 100 times lower than CsA (Peters et al., Drugs46:746-94, 1993). Tacrolimus and its formulations are described, forexample, in 2004 Physicians' Desk Reference® (2003) Thomson Healthcare,58th ed., and U.S. Pat. Nos. 4,894,366; 4,929,611; and 5,164,495.

Sirolimus (rapamycin) is an immunosuppressive lactam macrolideproduceable, for example, by Streptomyces hygroscopicus. Numerousderivatives of sirolimus and its analogs and their formulations areknown and described, for example, in 2004 Physicians' Desk Reference®(2003) Thomson Healthcare, 58th ed., European Patent EP 0467606; PCTPublication Nos. WO 94/02136, WO 94/09010, WO 92/05179, WO 93/11130, WO94/02385, WO 95/14023, and WO 94/02136, and U.S. Pat. Nos. 5,023,262;5,120,725; 5,120,727; 5,177,203; 5,258,389; 5,118,677; 5,118,678;5,100,883; 5,151,413; 5,120,842; and 5,256,790.

CD40 Fragments

The invention also features fragments of CD40 that include the epitopethat is specifically bound by the 2C10 antibody. The 2C10 antibody wasraised against the extracellular portion of the CD40 polypeptide; it isthus believed that this antibody reacts with a portion of this sequence(SEQ ID NOS:5 and 6).

The invention therefore features CD40 fragments (e.g., fewer than 150,120, 100, 80, 70, 60, 50, 40, 30, 20, 18, 15, 12, 11, 10, 9, 8, or 7)amino acids in length that are specifically bound by the 2C10 antibody.In certain embodiments, the fragment is 8-10, 8-12, 8-15, 8-20, 8-30,8-40, 8-50, 8-60, 8-70, 8-80, or 8-100 amino acids in length. In otherembodiments, the fragment is 7-10, 7-12, 7-15, 7-20, 7-30, 7-40, 7-50,7-60, 7-70, 7-80, or 7-100 in length.

Fusion Proteins

The invention also features fusion protein that includes a fragmentdescribed herein and a heterologous sequence. In certain embodiments,one of the fusion partners is the Fc protein (e.g., mouse Fc or humanFc). The fusion may also be a sequence useful for antibody production,e.g., a maltose binding protein or GST. In other embodiments, the fusionprotein is a purification or detection tag, for example, proteins thatmay be detected directly or indirectly such as green fluorescentprotein, hemagglutinin, or alkaline phosphatase), DNA binding domains(for example, GAL4 or LexA), gene activation domains (for example, GAL4or VP16), purification tags, or secretion signal peptides (e.g.,preprotyrypsin signal sequence). In other embodiments, the fusionpartner may be a tag, such as c-myc, poly histidine, or FLAG. Eachfusion partner may contain one or more domains, e.g., a preprotrypsinsignal sequence and FLAG tag.

Production of CD40 Fragments and Fusion Proteins

The CD40 fragments and fusion proteins described herein may be producedby transformation of a suitable host cell with a polynucleotide moleculeencoding the polypeptide fragment or fusion protein in a suitableexpression vehicle.

Those skilled in the field of molecular biology will understand that anyof a wide variety of expression systems may be used and that the precisesystem or host cell used is not critical to the invention. Exemplaryexpression systems include prokaryotic hosts (e.g., E. coli) andeukaryotic hosts (e.g., S. cerevisiae, insect cells, e.g., Sf21 cells,or mammalian cells, e.g., NIH 3T3, HeLa, or preferably COS cells). Suchcells are available from a wide range of sources (e.g., the AmericanType Culture Collection, Manassas, Va.). The method of transformation ortransfection and the choice of expression vehicle will depend on thehost system selected. Transformation and transfection methods aredescribed, e.g., in Kucherlapati et al. (CRC Crit. Rev. Biochem.16:349-379, 1982) and in DNA Transfer to Cultured Cells (eds., Ravid andFreshney, Wiley-Liss, 1998); and expression vehicles may be chosen fromthose provided, e.g., in Vectors: Expression Systems: EssentialTechniques (ed., Jones, Wiley & Sons Ltd., 1998).

Once the recombinant CD40 polypeptide fragment or fusion protein isexpressed, it can be isolated, e.g., using affinity chromatography. Inone example, an antibody raised against the fragment or fusion protein(e.g., the 2C10 antibody) may be attached to a column and used toisolate the polypeptide fragment or fusion protein. Lysis andfractionation of fragment- or fusion protein-harboring cells prior toaffinity chromatography may be performed by standard methods (see, e.g.,Methods in Enzymology, volume 182, eds., Abelson, Simon, and Deutscher,Elsevier, 1990).

Once isolated, the CD40 polypeptide fragment or fusion protein can, ifdesired, be further purified, e.g., by high performance liquidchromatography (see e.g., Fisher, Laboratory Techniques in Biochemistryand Molecular Biology, eds., Work and Burdon, Elsevier, 1980; andScopes, Protein Purification: Principles and Practice, Third Edition,ed., Cantor, Springer, 1994).

The CD40 polypeptide fragments or fusion proteins can also be producedby chemical synthesis (e.g., by the methods described in Solid PhasePeptide Synthesis, 2nd ed., 1984, The Pierce Chemical Co., Rockford,Ill.; and Solid-Phase Synthesis: A Practical Guide, ed., Kates andAlbericio, Marcel Dekker Inc., 2000).

OTHER EMBODIMENTS

All patents, patent applications, and publications mentioned in thisspecification are herein incorporated by reference to the same extent asif each independent patent, patent application, or publication wasspecifically and individually indicated to be incorporated by reference.

What is claimed is:
 1. A polynucleotide encoding an antibody orantigen-binding fragment thereof that specifically binds to an epitopepresent on CD40, wherein the heavy chain variable region of the antibodyor antigen-binding fragment thereof comprises the hypervariable regionsset forth in amino acids 20-132 of SEQ ID NO:2, and the light chainvariable region of the antibody or antigen-binding fragment thereofcomprises the hypervariable regions set forth in amino acids 23-128 ofSEQ ID NO:4.
 2. The polynucleotide of claim 1, wherein the epitope ispresent within the sequence of amino acids 8-60 of SEQ ID NO:6.
 3. Thepolynucleotide of claim 1, wherein the antibody or antigen-bindingfragment thereof blocks B lymphocyte activation by CD154-expressingJurkat cells in vitro.
 4. The polynucleotide of claim 1, wherein theantibody or antigen-binding fragment thereof inhibits B lymphocyte CD23,CD80, or CD86 expression.
 5. The polynucleotide of claim 3, wherein theB lymphocyte is a rhesus B lymphocyte.
 6. The polynucleotide of claim 1,wherein the CD40 is rhesus CD40 or human CD40.
 7. The polynucleotide ofclaim 1, wherein the constant regions of the antibody are human constantregions.
 8. The polynucleotide of claim 1, wherein the antibody is ahumanized antibody or a human antibody.
 9. The polynucleotide of claim1, wherein the antibody is a monoclonal antibody.
 10. The polynucleotideof claim 1, wherein the heavy chain variable region of the antibody orantigen-binding fragment thereof comprises amino acids 20-132 of SEQ IDNO:2, and the light chain variable region of the antibody orantigen-binding fragment thereof comprises amino acids 23-128 of SEQ IDNO:4.
 11. The polynucleotide of claim 1, wherein the antigen-bindingfragment is an antibody that lacks an Fc portion.
 12. The polynucleotideof claim 1, wherein the antigen-binding fragment is a F(ab′)₂, a Fab, anFv, or an scFv.
 13. A vector encoding the polynucleotide of claim
 1. 14.A cell comprising the vector of claim
 13. 15. The cell of claim 13,wherein said cell is eukaryotic.
 16. The cell of claim 14, wherein saidcell is mammalian.
 17. The cell of claim 13, wherein said cell isprokaryotic.